The present invention relates generally to medical imaging and developing imaging protocols and, more particularly, to a method and apparatus to determine a likelihood of artifact presence in a reconstructed image and displaying the likelihood of artifact presence to an operator for evaluation. The present invention enables redevelopment and/or redesigning of the imaging protocol based upon the likelihood of artifact presence in a reconstructed image.
Typically, helical reconstruction algorithms produce artifacts in a reconstructed image due to data inconsistencies generated by a patient translation in a z direction during gantry rotation. While the intensity of artifacts depends in large part on the particular scanning parameters of the scanning session, generally these artifacts are most intense around high contrast interfaces such as bone/tissue (ribs) or air/tissue cavities. Additionally, artifact intensity typically increases with pitch but may also change depending upon the implemented helical reconstruction algorithm and detector width used to acquire imaging data.
With known imaging systems, it is incumbent upon the scanner operator to understand the artifact intensity with prescribing a patient examination. Typically, the operator learns from experience whether a particular scan procedure will result in an increased or decreased artifact presence. Moreover, the operator must be cognizant of scan versus artifact presence for a number of scanning possibilities without the benefit of any visual queues. While under some circumstances a large artifact presence in the final reconstructed image is not bothersome, for other scan procedures a reconstructed image absent visual artifacts is paramount.
For single slice CT systems that employ simple reconstruction weighting schemes, the scanning operators typically utilize the helical pitch of the scan as an indication of expected artifact. This can be difficult however for a new or inexperienced operator or for a CT system that has numerous operating modes. Furthermore, in multi-slice CT systems, with various pitch and detector width selections, an operator or technologist may find it very difficult to remember what to expect for each set of operating conditions.
Therefore, it would be desirable to design an apparatus and method that determines and visually displays a likelihood of artifact presence in a reconstructed image for evaluation by a scan system operator. Further, it would be desirable to design such a system that enables the system operator to provide feedback to the system such that artifact presence is reduced in a subsequent imaging session.